Tuesday, November 08, 2005

Dr. Tatiana on H5N1 & Evolution

“Anyone who supposes that evolution doesn't happen, or doesn't matter, should spare a thought for H5N1, the virus causing avian flu. If we're unlucky, this virus will give us a nasty demonstration of evolution in action."

"The influenza virus that caused the infamous Spanish flu pandemic of 1918 had only eight genes - but it brought about more than 20 million human deaths. And alas, its lethality cannot be blithely attributed to wartime deprivation. For one thing, it was particularly deadly in young, healthy adults. For another, in a remarkable feat of genetic engineering, a team of biologists recently reconstructed the 1918 virus and used it to infect mice. The results are sobering. The 1918 virus is far, far more lethal in mice than are other human flu viruses.

H5N1 also has eight genes (by way of comparison, humans have about 20,000). So far, the virus' effects have been more modest than those of the 1918 influenza: It has killed a lot of birds and about 60 people. That's still worrying, however, because it has killed more than half of the people it has infected. For a virus, that is a high death toll.“

“But the most important point is this: Viruses and other pathogens evolve in ways that we can understand and, to some extent, predict. Whether it's preventing a flu pandemic or tackling malaria, we can use our knowledge of evolutionary processes in powerful and practical ways, potentially saving the lives of tens of millions of people. So let's not strip evolution from the textbooks, or banish it from the class, or replace it with ideologies born of wishful thinking. If we do, we might find ourselves facing the consequences of natural selection.”